I don't know that Christianity is collapsing in the US, so much as institutional church is collapsing, or more specifically Christendom, which is not the same as Christianity. Christendom is more oriented towards the items you wrote about. Christendom is more like empire, than Christianity. It's about being in power and determining who's in and who's out. I'm glad to see that collapse. There are some pretty good books on this subject, or ones that touch on what is collapsing and why. I recommend Church Refugees, it's a recent look at why people leave the church. It mirrors many of the things you talk about in your article.